<!DOCTYPE html>
<html>
<head>
    <title>Canvas射箭小游戏</title>
</head>
<style type="text/css">
    body{
        margin:0;
        background:#222;

        margin:20px;
    }
    svg{
        width:100%;
        height:100%;
        position:fixed;
        top:0;
        left:0;
    }
    span{
        color:white;
        font-family:sans-serif;
        opacity:.3;
    }
</style>
<script src="http://demo.mycodes.net/youxi/canvas_shejian/js/TweenMax.min.js"></script>
<script src="http://demo.mycodes.net/youxi/canvas_shejian/js/MorphSVGPlugin.min.js"></script>

<body>
    <svg id="game" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1000 400" overflow="visible">
        <linearGradient id="ArcGradient" >
            <stop offset="0"  stop-color="#fff" stop-opacity=".2"/>
            <stop offset="50%" stop-color="#fff" stop-opacity="0"/>
        </linearGradient>
        <path id="arc" fill="none" stroke="url(#ArcGradient)" stroke-width="4" d="M100,250c250-400,550-400,800,0"  pointer-events="none"/>
        <defs>
            <g id="arrow">
                <line x2="60" fill="none" stroke="#888" stroke-width="2" />
                <polygon fill="#fdfdfd" points="64 0 58 2 56 0 58 -2" />
                <polygon fill="#88ce02" points="2 -3 -4 -3 -1 0 -4 3 2 3 5 0" />
            </g>
        </defs>
        <g id="target">
            <path fill="#FFF" d="M924.2,274.2c-21.5,21.5-45.9,19.9-52,3.2c-4.4-12.1,2.4-29.2,14.2-41c11.8-11.8,29-18.6,41-14.2 C944.1,228.3,945.7,252.8,924.2,274.2z" />
            <path fill="#F4531C" d="M915.8,265.8c-14.1,14.1-30.8,14.6-36,4.1c-4.1-8.3,0.5-21.3,9.7-30.5s22.2-13.8,30.5-9.7 C930.4,235,929.9,251.7,915.8,265.8z" />
            <path fill="#FFF" d="M908.9,258.9c-8,8-17.9,9.2-21.6,3.5c-3.2-4.9-0.5-13.4,5.6-19.5c6.1-6.1,14.6-8.8,19.5-5.6 C918.1,241,916.9,250.9,908.9,258.9z" />
            <path fill="#F4531C" d="M903.2,253.2c-2.9,2.9-6.7,3.6-8.3,1.7c-1.5-1.8-0.6-5.4,2-8c2.6-2.6,6.2-3.6,8-2 C906.8,246.5,906.1,250.2,903.2,253.2z" />
        </g>
        <g id="bow" fill="none" stroke-linecap="round" vector-effect="non-scaling-stroke" pointer-events="none">
            <polyline fill="none" stroke="#ddd" stroke-linecap="round" points="88,200 88,250 88,300"/>
            <path fill="none" stroke="#88ce02" stroke-width="3" stroke-linecap="round" d="M88,300 c0-10.1,12-25.1,12-50s-12-39.9-12-50"/>
        </g>
        <g class="arrow-angle"><use x="100" y="250" xlink:href="#arrow"/></g>
        <clipPath id="mask">
            <polygon opacity=".5" points="0,0 1500,0 1500,200 970,290 950,240 925,220 875,280 890,295 920,310 0,350" pointer-events="none"/>
        </clipPath>
        <g class="arrows" clip-path="url(#mask)"  pointer-events="none">
        </g>
        <g class="miss" fill="#aaa" opacity="0" transform="translate(0, 100)">
            <path d="M358 194L363 118 386 120 400 153 416 121 440 119 446 203 419 212 416 163 401 180 380 160 381 204"/>
            <path d="M450 120L458 200 475 192 474 121"/>
            <path d="M537 118L487 118 485 160 515 162 509 177 482 171 482 193 529 199 538 148 501 146 508 133 537 137"/>
            <path d="M540 202L543 178 570 186 569 168 544 167 546 122 590 116 586 142 561 140 560 152 586 153 586 205"/>
            <path d="M595,215l5-23l31,0l-5,29L595,215z M627,176l13-70l-41-0l-0,70L627,176z"/>
        </g>
        <g class="bullseye" fill="#F4531C" opacity="0">
            <path d="M322,159l15-21l-27-13l-32,13l15,71l41-14l7-32L322,159z M292,142h20l3,8l-16,8 L292,142z M321,182l-18,9l-4-18l23-2V182z"/>
            <path d="M340 131L359 125 362 169 381 167 386 123 405 129 392 183 351 186z"/>
            <path d="M413 119L402 188 450 196 454 175 422 175 438 120z"/>
            <path d="M432 167L454 169 466 154 451 151 478 115 453 113z"/>
            <path d="M524 109L492 112 466 148 487 155 491 172 464 167 463 184 502 191 513 143 487 141 496 125 517 126z"/>
            <path d="M537 114L512 189 558 199 566 174 533 175 539 162 553 164 558 150 543 145 547 134 566 148 575 124z"/>
            <path d="M577 118L587 158 570 198 587 204 626 118 606 118 598 141 590 112z"/>
            <path d="M635 122L599 198 643 207 649 188 624 188 630 170 639 178 645 162 637 158 649 143 662 151 670 134z"/>
            <path d="M649,220l4-21l28,4l-6,25L649,220z M681,191l40-79l-35-8L659,184L681,191z"/>
        </g>
        <g class="hit" fill="#ffcc00" opacity="0" transform="translate(180, -80) rotate(12) ">
            <path d="M383 114L385 195 407 191 406 160 422 155 418 191 436 189 444 112 423 119 422 141 407 146 400 113"/>
            <path d="M449 185L453 113 477 112 464 186"/>
            <path d="M486 113L484 130 506 130 481 188 506 187 520 131 540 135 545 119"/>
            <path d="M526,195l5-20l22,5l-9,16L526,195z M558,164l32-44l-35-9l-19,51L558,164z"/>
        </g>
<!--     <line x1= "875", y1= "280", x2= "925", y2= "220" stroke="red"/>

    <circle class="point" r="7" fill="purple" opacity=".4"/> -->
</svg>
<span>点击弓然后射箭！</span>
</body>
<script type="text/javascript">
    var svg = document.querySelector("svg");
    var cursor = svg.createSVGPoint();
    var arrows = document.querySelector(".arrows");
    var randomAngle = 0;

// center of target
var target = {
    x: 900,
    y: 249.5
};

// target intersection line segment
var lineSegment = {
    x1: 875,
    y1: 280,
    x2: 925,
    y2: 220
};

// bow rotation point
var pivot = {
    x: 100,
    y: 250
};
aim({
    clientX: 320,
    clientY: 300
});

// set up start drag event
window.addEventListener("mousedown", draw);

function draw(e) {
    // pull back arrow
    randomAngle = (Math.random() * Math.PI * 0.03) - 0.015;
    TweenMax.to(".arrow-angle use", 0.3, {
        opacity: 1
    });
    window.addEventListener("mousemove", aim);
    window.addEventListener("mouseup", loose);
    aim(e);
}

function aim(e) {
    // get mouse position in relation to svg position and scale
    var point = getMouseSVG(e);
    point.x = Math.min(point.x, pivot.x - 7);
    point.y = Math.max(point.y, pivot.y + 7);
    var dx = point.x - pivot.x;
    var dy = point.y - pivot.y;
    // Make it more difficult by adding random angle each time
    var angle = Math.atan2(dy, dx) + randomAngle;
    var bowAngle = angle - Math.PI;
    var distance = Math.min(Math.sqrt((dx * dx) + (dy * dy)), 50);
    var scale = Math.min(Math.max(distance / 30, 1), 2);
    TweenMax.to("#bow", 0.3, {
        scaleX: scale,
        rotation: bowAngle + "rad",
        transformOrigin: "right center"
    });
    var arrowX = Math.min(pivot.x - ((1 / scale) * distance), 88);
    TweenMax.to(".arrow-angle", 0.3, {
        rotation: bowAngle + "rad",
        svgOrigin: "100 250"
    });
    TweenMax.to(".arrow-angle use", 0.3, {
        x: -distance
    });
    TweenMax.to("#bow polyline", 0.3, {
        attr: {
            points: "88,200 " + Math.min(pivot.x - ((1 / scale) * distance), 88) + ",250 88,300"
        }
    });

    var radius = distance * 9;
    var offset = {
        x: (Math.cos(bowAngle) * radius),
        y: (Math.sin(bowAngle) * radius)
    };
    var arcWidth = offset.x * 3;

    TweenMax.to("#arc", 0.3, {
        attr: {
            d: "M100,250c" + offset.x + "," + offset.y + "," + (arcWidth - offset.x) + "," + (offset.y + 50) + "," + arcWidth + ",50"
        },
        autoAlpha: distance/60
    });

}

function loose() {
    // release arrow
    window.removeEventListener("mousemove", aim);
    window.removeEventListener("mouseup", loose);

    TweenMax.to("#bow", 0.4, {
        scaleX: 1,
        transformOrigin: "right center",
        ease: Elastic.easeOut
    });
    TweenMax.to("#bow polyline", 0.4, {
        attr: {
            points: "88,200 88,250 88,300"
        },
        ease: Elastic.easeOut
    });
    // duplicate arrow
    var newArrow = document.createElementNS("http://www.w3.org/2000/svg", "use");
    newArrow.setAttributeNS('http://www.w3.org/1999/xlink', 'href', "#arrow");
    arrows.appendChild(newArrow);

    // animate arrow along path
    var path = MorphSVGPlugin.pathDataToBezier("#arc");
    TweenMax.to([newArrow], 0.5, {
        force3D: true,
        bezier: {
            type: "cubic",
            values: path,
            autoRotate: ["x", "y", "rotation"]
        },
        onUpdate: hitTest,
        onUpdateParams: ["{self}"],
        onComplete: onMiss,
        ease: Linear.easeNone
    });
    TweenMax.to("#arc", 0.3, {
        opacity: 0
    });
    //hide previous arrow
    TweenMax.set(".arrow-angle use", {
        opacity: 0
    });
}

function hitTest(tween) {
    // check for collisions with arrow and target
    var arrow = tween.target[0];
    var transform = arrow._gsTransform;
    var radians = transform.rotation * Math.PI / 180;
    var arrowSegment = {
        x1: transform.x,
        y1: transform.y,
        x2: (Math.cos(radians) * 60) + transform.x,
        y2: (Math.sin(radians) * 60) + transform.y
    }

    var intersection = getIntersection(arrowSegment, lineSegment);
    if (intersection.segment1 && intersection.segment2) {
        tween.pause();
        var dx = intersection.x - target.x;
        var dy = intersection.y - target.y;
        var distance = Math.sqrt((dx * dx) + (dy * dy));
        var selector = ".hit";
        if (distance < 7) {
            selector = ".bullseye"
        }
        showMessage(selector);
    }

}

function onMiss() {
    // Damn!
    showMessage(".miss");
}

function showMessage(selector) {
    // handle all text animations by providing selector
    TweenMax.killTweensOf(selector);
    TweenMax.killChildTweensOf(selector);
    TweenMax.set(selector, {
        autoAlpha: 1
    });
    TweenMax.staggerFromTo(selector + " path", .5, {
        rotation: -5,
        scale: 0,
        transformOrigin: "center"
    }, {
        scale: 1,
        ease: Back.easeOut
    }, .05);
    TweenMax.staggerTo(selector + " path", .3, {
        delay: 2,
        rotation: 20,
        scale: 0,
        ease: Back.easeIn
    }, .03);
}

function getMouseSVG(e) {
    // normalize mouse position within svg coordinates
    cursor.x = e.clientX;
    cursor.y = e.clientY;
    return cursor.matrixTransform(svg.getScreenCTM().inverse());
}

function getIntersection(segment1, segment2) {
    // find intersection point of two line segments and whether or not the point is on either line segment
    var dx1 = segment1.x2 - segment1.x1;
    var dy1 = segment1.y2 - segment1.y1;
    var dx2 = segment2.x2 - segment2.x1;
    var dy2 = segment2.y2 - segment2.y1;
    var cx = segment1.x1 - segment2.x1;
    var cy = segment1.y1 - segment2.y1;
    var denominator = dy2 * dx1 - dx2 * dy1;
    if (denominator == 0) {
        return null;
    }
    var ua = (dx2 * cy - dy2 * cx) / denominator;
    var ub = (dx1 * cy - dy1 * cx) / denominator;
    return {
        x: segment1.x1 + ua * dx1,
        y: segment1.y1 + ua * dy1,
        segment1: ua >= 0 && ua <= 1,
        segment2: ub >= 0 && ub <= 1
    };
}
</script>
</html>